Drug Interaction Report

Flecainide and Clomipramine: Interaction Details

A pharmacist-reviewed analysis of the Flecainide and Clomipramine interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Clomipramine

Anafranil Calmera Caniquell Clomicalm
+

Flecainide

Tambocor®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 300 documented Flecainide interactions, 270 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Major

What happens

Increased clomiPRAMINE exposure and an increased risk of QT interval prolongation

Interaction Deep Dive

Concomitant use of flecainide with other drugs that may prolong the QT interval, such as clomiPRAMINE, should be undertaken with caution due to the potential for additive effects on the QT interval and increased serious cardiac events, including torsade de pointes1. Concomitant use of clomiPRAMINE with CYP2D6 inhibitors, such as flecainide may also increase the exposure of clomiPRAMINE and may require lower doses than usually prescribed for either clomiPRAMINE or the other drug. Furthermore, whenever one of these drugs is withdrawn from co-therapy, an increased dose of clomiPRAMINE may be required. It is desirable to monitor clomiPRAMINE exposure whenever is coadministered with flecainide 2.

Why it happens (mechanism)

Increased clomiPRAMINE exposure; additive QT interval prolongation

Common questions

Can I take Flecainide and Clomipramine together?

Increased clomiPRAMINE exposure and an increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.

How serious is the Flecainide and Clomipramine interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

  • Does my dose of Flecainide or Clomipramine need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there a safer alternative to one of these medications for me?

References (2)

  1. Product Information: flecainide acetate oral tablets, flecainide acetate oral tablets. Roxane Laboratories, Inc, Columbus, OH, 2009. DailyMed
  2. Product Information: ANAFRANIL(TM) oral capsules, clomipramine hydrochloride oral capsules. SpecGx LLC (per Dailymed), Webster Groves, MO, 2024. DailyMed
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Clomipramine

Keep reading about Clomipramine

All Clomipramine interactions (197)
Also serious with: Metoclopramide Injection Metoclopramide Nasal Spray Linezolid Injection Penicillin V Potassium
Flecainide

Keep reading about Flecainide

All Flecainide interactions (300) Flecainide drug information
Also serious with: Nirmatrelvir Mesoridazine Pimozide Mavorixafor
Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Clomipramine + Activated Charcoal Grapefruit Henbane Scopolia St. John's Wort 1,3-dmaa Acacia Rigidula Active Hexose Correlated Compound (ahcc) + 228 more
Flecainide + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Sida Cordifolia 1,3-dmaa + 78 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.